The investigation into the March 18 incident at Hawthorne
Army Depot blames human error for the accident that killed seven Marines and
injured eight others. Located in Nevada, Hawthorne is operated by Redstone Arsenal-based Army
Materiel Command.

According to a Marine report, the deaths and injuries occurred
during a live-fire night exercise on a range at the depot when a 60mm mortar round
exploded in the area of the section's firing position.

"The investigation
established that human error was the cause of the mortar mishap. The Marines employing one of the mortars did
not follow correct procedures, resulting in the detonation of a high explosive
round at the mortar position," the report concludes. The mortar system itself
functioned properly, according to the report.

However, it concludes participants - all members of the 1st
Battalion, 9th Marine Division - had not undergone appropriate
training ahead of the live-fire event.

The investigation led to the dismissal of Lt. Col. Andrew
McNulty, commanding officer of the 1st Battalion, 9th Marine Division. He was
relieved of duties May 8 by Brig. Gen. James Lukeman, commanding general of
Second Marine Division based at Campo Lejeune, who oversaw the investigation.

Capt. Kelby Breivogel, the company commander of Company A,
and Chief Warrant Officer 3 Douglas Derring, the battalion's Marine infantry
weapons officer, were also relieved of their duties. Lukeman said they were
relieved of their duties due to "lost trust and confidence in (the commanders')
ability to ensure proper preparation for, and conduct of, live-fire training
events."

Lt. Col. Corey Collier assumed command of 1st Battalion, 9th
Marines, on May 23. Lukeman said no criminal charges are anticipated as a
result of the investigation.

Hawthorne Army Depot serves as a demilitarization facility
for conventional ammunition.